The present disclosure relates to migrating a virtual machine, which generates stateful offload data packets, from a first system to a second system. More particularly, the present disclosure relates to extracting hardware state data from a source network adapter and copying the extracted hardware state data to a destination system during the migration.
Modern communication network adapters support “stateful” offload data transmission formats in which the network adapters perform particular processing tasks in order to reduce a host system's processing load. Typical stateful offload formats include Remote Direct Memory Access (RDMA), Internet Wide RDMA Protocol (iWARP), Infiniband (IB), and TCP Offload Engine (TOE). In order to support the stateful offload formats, the network adapters restrict the “state” for any given virtual machine connection to the context of the network adapter's instance corresponding to the virtual machine. Stateful offload information that represents this context includes hardware state data that describes hardware properties on a per virtual machine basis, such as information corresponding to connections, registers, memory registrations, structures used to communicate with the virtual machine (Queue Pairs, Completion Queues, etc.), and other miscellaneous data structures, such as address resolution protocol (ARP) tables.